1. Field of the Invention
The present invention relates to a semiconductor device using a semiconductor element.
2. Description of the Related Art
Memory devices using semiconductor elements are broadly classified into two categories: a volatile device that loses stored data when power supply stops, and a non-volatile device that retains stored data even when power is not supplied.
A typical example of a volatile memory device is a dynamic random access memory (DRAM). A DRAM stores data in such a manner that a transistor included in a memory element is selected and electric charge is accumulated in a capacitor.
Another example of a volatile memory device is a static random access memory (SRAM). An SRAM remains stored data with a circuit such as a flip-flop.
A typical example of a non-volatile memory device is a flash memory. A flash memory includes a floating gate between a gate electrode and a channel formation region in a transistor and stores data by holding charge in the floating gate.
Such a memory device using a semiconductor element includes a memory cell array including a plurality of memory cells and a driver circuit arranged in the periphery of the memory cell array as main components, and the size of the semiconductor device is limited by the area of the driver circuit. That is to say, even when only the area of a memory cell is reduced, a semiconductor device cannot be wholly miniaturized unless the area of the driver circuit can be reduced. Therefore, it is important to reduce the area of a driver circuit in miniaturizing a semiconductor device.
For example, in a semiconductor device disclosed in Patent Document 1, adjacent wiring regions in which wirings connecting a memory cell array portion and a peripheral circuit portion are formed have the same layout.